Grinding machine



Oct. 10, 1933.

F.KURATH GRINDING MACHINE Filed Feb. 25, 1929 y w d I Fatenteol first. 10 19333 his term" Grim --'1,929,v ic GRINDING MACHINE Franz Kurath, Shicagc, llli. assignor to Economy Fuse and Manufacturing Co,

Chicago, 111., a

corporation of New York 7 Application Fcbruaryfiiu, 1929. SerialNo. 342,521 3 claims; (c1; 51-405) more particularly to a grinding machine which has been especially developed .to be used in removing the fin or flash from molded phenolic condensation products.

The removal of the fin some form of grinding or tooling means must be used and the operation must be made both cilicient and accurate. The common inethod has been for an operator to manually hold the article against a grinding wheel but such depends a tor andnecessarily results insome spoilage ofmaterial.

be very small in size, it is not an operation great deal upon the skill of theopera- Furthermore, since the articles may desired to use a complicated grinding machine in which there is a manual or mechanical feeding of either the grinding wheel or thework. a

It is, therefore, provide a grinding may be efficiently operation the purpose of my invention to device otsimplified form which invention 1. provide a mamounted upon a work spindle and upon manual operation of the means for caused to "The movement of the rotating the work, a grinding wheel is feed impositively towardsthe work.

by an adjustable guard.

It is further an object of my invention to so construct is positively moved from lution of the drive spindle H ished article may be removed and another placed" my machine that the grinding wheel the work at each revowhereupon the fin in position.

Further objects and advantages of my improved construction will be more readily apparent from the description taken in connection with the attached drawing in which- Figure 1 is a top plan apparatus. Figure 2 hand end Figure 3 is an end elevation View of the complete is a forward vertical elevation.

from the right of Figiue 2.

V In the drawing 1 show one embodiment of my invention from which the general principles will be apparent. A base 1 a pair of serves as a mounting for bearing brackets 2 and 3, forming a 1 pulley '7.

The spindle shaft 4 rotates in pivoted presents 'a problem since used for the above mentioned or for other purposes whichiwill be readily apparent.

In carrying out my chine whereby the articles may be 1 at the end of each operation.

grinding wheel is limited.

.of the drive shaft 27 for each article.

bushings 8 and 9 men are adapted to be connected to a pair of bell crank levers'10 and 11 whereby the bell crank levers will pivot about the shaft i as a center. The horizontally extending 211211312 and 13 of the bell crank levers carryat ()9 their outer ends a laterally extending spindle support 14 connected to a bushing 15. A spindle secured a guard 20 which may be ad- 7 It is my purpose to allow the grinding wheel to have a freegravital movement towards'the work. I, therefore, provide positive means for lifting the grinding wheel away fromthework It is obvious that the grinding wheel could be supported for movement in any desired path, but I preferably swing the wheel in an arc, as shown, about the spindle shaft 4. The means for lifting the grinding wheel. consists ofythe downwardly extending arms 23 of the bell crank levers which are connected to' a link 24. The link 24 is adjustably connected to a slotted bar 25 whereby the throw of'the grinding wheel may be varied in accordance with different classes of work by suitable adjustment of the connection.

The bar 25' is provided with a longitudinal slot 26 which receives and is guided by shaft 27. Movement is imparted to thebar 25and thus to the grinding wheel due to the cooperation of a roller 28 mounted on 29 mounted on and turned by shaft 27. The shaft 27 which, upon each revolution, will positively raise the grinding wheel and allow it to gravitally fall towards the work also constitutes a drive shaft for rotating the work. Thus I show a bearing bracket 30 at one end of shaft 27 and a crank 31 and handle 32 at theother end whereby the shaft may be manually turned. Power means maybe used, if desired. but the grinding operation usually requires only a single rotation The base 1 is provided with a guide slot 33 whereby an adjustable carriage se is supported for sliding movement. The carriage 34 is formed with a pair of 1 bearing brackets 3536 having bearing bushthe bar 25 with a tooth ings 3738 for a pinion shaft 39. A pinion gear 40 is fixed to shaft 39 between the brackets 3536 and meshes with a gear 41, which is keyed for sliding movement longitudinally of shaft 27. Upon the inner end of the work shaft 42 may be mounted various fixtures for securing the work for rotation adjacent to the grinding wheel.

My grinding machine is most advantageous When it is desired to remove the circular flash from a molded article which may be readily mounted so as to rotate, thus the article is mounted on the end 42 of shaft 39 or upon a fixture which is secured thereto. Upon one revolution of the shaft 27 by the handle 32, the article will be rotated a plurality of times due to the intermeshing gears 40 and ll and the grinding wheel, which is rotated from a power source, will be allowed to gravitally fall until it contacts with the article and grinds away the flash. The guard 20 is so adjusted that the arm 22 will rest upon a portion of the surface of the rotating article and prevent the grinding from proceeding too far.

It will be apparent that the arm carrying the grinding wheel moves downward only by the force of gravity so that the guard 20 will easily prevent further movement of the grinding wheel. Upon the completion of the operation by the rotation of shaft 27, the grinding wheel is moved back to its inoperative position due to the cooperation of the cam 29 which turns with the shaft 27 and the roller 28 mounted on the shiftable bar 25. In working upon the relatively small parts for which this machine is designed the operator may quickly and efliciently mount an article, give the crank one revolution and remove the finished article. It is, therefore, apparent that the apparatus is most efficient. The slidable-carriage 34 may be moved back and forth longitudinally of the shaft27 for diiferent classes of. Work.

As shown in the present embodiment, the grinding wheel is held on an arm and allowed to feed towards the work due to the force of gravity but in some cases it may be desired to move the grinding wheel against the work by some form of yieldable spring means, and such a construction is readily contemplated as being within the scope of my invention.

It is also apparent that the form of grinding wheel may be varied in accordance with the par ticular work to be operated upon, thus in some cases where the fin is on an angle face, the grinding wheel will have a corresponding angle.

'Although the apparatus shown is preferably used where it is desired to remove a completely circular fin, it may also be adapted to remove a fin from an irregular shaped article if the article has such a contour that the grinding wheel may be allowed to rise and fall as the surface of the article is moved due to the rotation of the work.

Although I have described my invention most particularly in connection with my preferred embodiment and my preferred use, still I do not intend to limit myself beyond the spirit of my invention as expressed in the appended claims.

I claim:

1. In a grinding device, means for supporting circular work for rotation comprising a work spindle, a drive spindle geared to said work spindle, means for manually rotating said drive spindle, grinding means pivotally supported for free gravital movement in an arc towards the work, means for positively moving the grinding means away from the work actuated by each revolution of said drive spindle, comprising a cam on said drive spindle, a slotted lever moved by said and a bell crank connected to said slotted lever, said bell crank comprising the mounting for the grinding means.

2. In a grinding device, a drive spindle, an arbor driven from said spindle adapted to have movnted thereon work to be ground, a single tooth cam mounted on said driving spindle, a bell crank lever pivotally supported parallel to the axes of said driving spindle and said arbor, a grinding wheel rotatably carried by one arm of said lever for gravital movement towards said work, means for rotating the grinding wheel from the pivotal supporting axis of the bell crank lever and means actuated by the cam at each revolution of the drive spindle for raising the grinding wheel out of contact with the work to enable a ready removal and attachment'of the work to be green 3. In a grinding device, a drive spindle, means for manually rotating the drive spindle, arbor supported above said drive spindle onv axis parallel thereto and driven from said spindle, said arbor being adapted to receive work to he oin-id, a cam mounted for rotation with said dr, dle, a bell crank lever pivotally supported on an axis parallel to the axes of said drive spindle and said work arbor, a grinding wheel rotatably carried by one arm of said lever for ravital movement downwards towards the work to be ground, means for rotating the grinding wheel from the pivotal supporting axis of the bell crank lever and means connected to the second arm of said bell crank lever actuated by said cam at each revolution of the drive spindle positively raising the grinding wheel out of Contact with the work toenable the removal and replacement thereof.

FRANZ KURATH. 

